The effect of p doping in InAs quantum dot lasers

We directly measure the modal gain and spontaneous emission spectra in three quantum dot structures that are nominally identical except for the level of p doping to ascertain the effect that p doping has on quantum dot lasers. The maximum modal gain increases at fixed quasi-Fermi level separation as the level of p doping increases from 0 to 15 to 50 acceptors per dot. The internal optical mode loss is similar for all three samples but the measured nonradiative current is larger for the p-doped structures.